316L Stainless Steel
metalaustenitic stainless steel
UNS S31603EN 1.4404DIN X2CrNiMo17-12-2AISI 316LSS 316L
Composition — UNS S31603 / ASTM F3184-16
| Element | Min % | Max % | Notes |
|---|---|---|---|
| Fe | bal. | balance | |
| Cr | 16.00 | 18.000 | |
| Ni | 10.00 | 14.000 | |
| Mo | 2.00 | 3.000 | Key for pitting resistance — differentiates 316 from 304 |
| Mn | — | 2.000 | |
| Si | — | 0.750 | |
| C | — | 0.030 | Low carbon ('L') reduces sensitisation risk during AM thermal cycles |
| P | — | 0.045 | |
| S | — | 0.030 | Lower S improves toughness and weldability |
| N | — | 0.100 | Nitrogen stabilises austenite; AM atmosphere control prevents N loss |
Mechanical & thermal properties — 6 conditions
| Property | LPBF as-built (XY) | LPBF as-built (Z) | LPBF as-built, machined surface (XY) | LPBF stress-relieved (XY) | LPBF solution-annealed (XY) | LPBF + HIP (isotropic) |
|---|---|---|---|---|---|---|
| Elastic modulus | 193 GPa | — | — | — | — | — |
| Yield strength (0.2%) | 450–560 MPa | 420–530 MPa | — | 440–540 MPa | 200–270 MPa | 190–250 MPa |
| Ultimate tensile strength | 580–700 MPa | 540–640 MPa | — | 560–660 MPa | 500–570 MPa | 490–560 MPa |
| Elongation at break | 30.0–55.0 % | 25.0–50.0 % | — | 32.0–55.0 % | 45.0–65.0 % | 50.0–70.0 % |
| Reduction in area | 65.0 % | — | — | — | — | — |
| Hardness (HV) | 200–260 HV10 | 195–255 HV10 | — | 190–250 HV10 | 140–175 HV10 | 135–170 HV10 |
| Fatigue strength | 160–240 MPa | — | 250–330 MPa | — | — | 240–320 MPa |
| Density | 7.99 g/cm³ | — | — | — | — | — |
| Thermal conductivity | 14.0 W/m·K | — | — | — | — | — |
| Specific heat | 500 J/(kg·K) | — | — | — | — | — |
| CTE | 16.5 µm/m·K | — | — | — | — | — |
Values shown as min–max where a spread is reported, otherwise as typical ± unit. Ranges reflect inter-source variation, not single-sample scatter. All values are for AM-processed specimens unless noted.
Engineering considerations
- Residual stress: 316L has high CTE (16.5 µm/m·K) and low thermal conductivity — large overhangs and solid blocks accumulate significant residual tensile stress. Use island scan strategy with interlayer rotation (e.g., 67°).
- Anisotropy: 5–15% strength reduction in Z vs XY. For load-critical parts, orient the primary load axis in the XY plane.
- Sensitisation risk is negligible in LPBF: low carbon content (≤0.03%) and rapid cooling prevent Cr₂₃C₆ precipitation at grain boundaries during AM thermal cycles.
- HIP decision: for fatigue-critical parts, HIP at 1100°C / 100 MPa / 4h eliminates sub-surface porosity and substantially extends fatigue life. Expect 30–50% cost premium.
- Post-processing sequence for corrosion-critical parts: LPBF → stress-relieve (650°C/1h) → rough machine → solution anneal (1050°C/30 min, water quench) → finish machine → electropolish.
- Binder jetting note: BJ 316L requires sintering at ~1360°C with ~15–20% linear shrinkage. Final density 98–99.5% — acceptable for structural but not pressure-critical applications without additional qualification.
- Electropolishing: removes 20–50 µm material; smooths Ra from ~10 µm to <0.5 µm. Essential for food-contact, pharmaceutical, and hygienic fluid applications.
- Powder degradation: limit re-use to 20–30 cycles without blending into virgin powder. Monitor oxygen content — O > 0.10% signals degradation and elevated sensitisation risk.
- Wall thickness: minimum printable wall ~0.3 mm; for structural load ≥0.8 mm recommended. Thin walls below 0.5 mm show higher porosity due to keyhole instability at edges.
Advantages
- Excellent corrosion resistance across wide pH range — superior to 304 in chloride environments due to Mo content
- As-built LPBF strength significantly exceeds wrought 316L minimum specifications
- Fully austenitic — non-magnetic (critical for MRI-adjacent medical equipment and sensitive electronic environments)
- Outstanding toughness at cryogenic temperatures down to -196°C (liquid nitrogen service)
- Good biocompatibility — ISO 10993 compliant for surgical instruments and implant-adjacent structures
- Well-established LPBF parameter sets available from all major machine OEMs — shortest time-to-print of any AM stainless
- Cost-effective feedstock compared to titanium or nickel superalloys
- Excellent powder flowability — high sphericity, minimal satellites, consistent layer spreading
Limitations
- Annealing eliminates the AM strength advantage — post-HT strength approaches wrought levels; re-specifying to wrought may be more cost-effective
- Susceptible to stress corrosion cracking (SCC) in hot (>60°C) concentrated chloride environments — use duplex 2205 or super-duplex for such media
- Low thermal conductivity (14 W/m·K) causes high thermal gradients and residual stress — warpage risk on large flat sections without scan strategy optimisation
- Not hardenable by heat treatment (austenitic) — for high-strength applications use maraging steel, 17-4PH, or Ti-6Al-4V
- As-built surface roughness (Ra 10–20 µm) incompatible with hygienic applications without post-machining and electropolishing
- Pitting corrosion resistance (PREN ~24) below super-duplex grades — review PREN = Cr + 3.3×Mo + 16×N against aggressive media
- Powder re-use must be controlled — oxygen and nitrogen pickup with repeated cycling degrades corrosion resistance and ductility
Typical applications
Heat exchangers and manifolds with complex internal channelsImpellers and pump components (corrosion-resistant)Surgical instruments and medical device housingsStructural brackets, mounts, and housingsTooling and fixtures for corrosive environmentsChemical reactor internals and fluid handling hardwareCryogenic vessel components and cold-plate structuresNuclear handling and containment hardwareOffshore and subsea connectors (industrial / energy sector)Food-contact and pharmaceutical processing equipment (post-polished)
Industries
aerospacemedicalindustrialenergy
Standards & certifications
ASTM-F3184established
316L (UNS S31603) parts produced by powder bed fusion — composition, powder, and minimum mechanical property requirements
aerospacemedicalindustrialenergy
ISO-52904established
Process quality assurance framework for safety-critical metal PBF parts
aerospacemedicaldefence
ASTM-E466established
Force-controlled fatigue testing for rotating and cyclic applications
aerospaceindustrialenergy
Compatible AM processes (5)
Other metal materials
Ti-6Al-4V Grade 5titanium alloy — alpha-beta17-4PH Stainless Steelmartensitic precipitation-hardening stainless steelAlSi10Mgaluminium-silicon alloy (cast grade adapted for AM)AlSi7Mg Aluminium Alloyhypoeutectic Al-Si-Mg precipitation-hardenable aluminium alloyInconel 718nickel superalloy — precipitation-hardenedInconel 625nickel superalloy — solid-solution-strengthenedCoCrMocobalt-chromium alloy (biomedical and aerospace grade)Maraging Steel MS1 (18Ni-300)maraging steel (ultra-high-strength, precipitation-hardened)H13 Tool Steelchromium-molybdenum hot-work tool steel
Related calculators
HT AdvisorStandard stress-relief, solution, and aging cycles for AM metals (Ti-6Al-4V, IN718, 17-4PH, AlSi10Mg, 316L, CuCrZr) per AMS, ASTM F3301, and AMS 5664.DistortionEstimate residual stress and distortion risk index (σ/σ_y) for LPBF and DED builds. Mercelis-Kruth model with preheat sensitivity table.VEDCompute LPBF VED from power, scan speed, hatch, and layer thickness. Includes process windows for common alloys.Melt PoolLPBF / DED melt pool depth, width, and cooling rate from the Rosenthal moving heat source solution. Absorptivity, thermal diffusivity, and solidification velocity.CE / PCMIIW and Pcm carbon equivalent for AM and DED steels. Preheating temperature estimate per EN ISO 13916 and AWS D1.1. Printability / weld-crack risk flag.HIPRecommended HIP temperature, pressure, and dwell time for AM metals per ASTM F3301, AMS 2801, and DEF STAN 02-835. Covers Ti alloys, Ni superalloys, steels.
Last reviewed: 2026-05-04 · v1 · Sources: ASTM-F3184, eos-316l-2023, renishaw-316l-2023, liu-2017-316l, saeidi-2015-ultra, debroy-2018-review, herzog-2016-metals, yadollahi-2017-fatigue, ASTM-E8, ASTM-E466, ISO-52904